require 'prime'

class Integer
  def divisor_list
    return [] if self <= 0
    return [1] if self == 1

    prime_division.map{|e| [*(0..e.last)].map{|v| e.first ** v }}.inject{|res, e| res.map{|t| e.map{|v| t * v}}.flatten}.sort
  end
end

class Yukicoder
  def initialize
    n = gets.to_i
    puts n.divisor_list.find{|i| i > 2}
  end
end

Yukicoder.new